There is currently an intense interest in novel carbon materials due to their unique and novel properties. For instance, the carbon materials may be useful to achieve high hydrogen energy storage, for use in purification processes as well as for different applications within the electrical/pharmaceutical sector. The properties are sensitive to the micro-structure of the carbon material, which can be varied by the degree of graphitisation and by introduction of rings other than hexagons in the network. Fullerenes are examples of novel graphitic structures where the introduction of a 12 pentagons in the hexagonal network results in closed shells (D. Huffman, Physics Today, p. 22, 1991). Carbon nanotubes are also an example of such possibilities (T. W. Ebbesen, Physics Today, p. 26, 1996). Open conical structures are yet another example of possible graphitic structures, but only three of five possible kinds have ever been synthesized (M. Ge and K. Sattler, Chemical Physics Letters, 220, P. 192, 1994; P. Li and K. Sattler, Mat. Res. Soc. Symp. Proc. 359, p. 87, 1995; R. Vincent, N. Burton, P. M. Lister and J. D. Wright, Inst. Phys, Conf. Ser. 138, p. 83, 1993).
Recent interest in fullerenes and nanotubes is amongst other connected to their use in the field of hydrogen storage. Hence, Fernando tubes a hydrogen storage of amazingly 75 wt % is reported (Hydrogen & Fuel Cell Letter, vol. 7/No. 2, February 1997) If this is the case, it will probably represent the break-through concerning a practical hydrogen storage system for use in the transportation sector. It is indicated that future fuel cell cars using this storage technology may achieve a range of about 8000 km.
In the case of fullerenes, more than 7 wt % of reversibly added hydrogen is achieved (R. M. Baum, Chem. Eng. News, 22, p. 8, 1993; Japanese Patent JP 27801 A2, Fullerene-based hydrogen storage media, 18,Aug. 1994; A. Hirsch, Chemistry of Fullerenes, Thieme Ferlag, Stuttgart, Ch. 5, p. 117, 1994). Fullerenes have also been used in a solid phase mixture with inter-metallic compounds or metals to achieve high contents of hydrogen, i.e. 24-26 H atoms per fullerenes molecule (B. P. Tarasov, V. N. Fokin, A. P. Moravsky, Y. M. Shul'ga, V. A. Yartys, Journal of Alloys and Compounds 153-254, p. 25, 1997). Flat graphitic material formed of stacks of two-guy mention sheets has high surface area of for adsorption of guest elements and compounds. However, in such materials, the absorption process is limited by diffusion. The larger the graphitic domain, the slower the adsorption will be. Of potential interest would be highly graphitic eyes to materials where domains were small so that the guest material would readily reach all the graphitic micro domains by percolation through the bulk carbon material. The accessibility to the micro-domains could be further enhanced if some or all the domain is had been topple logical discrimination, preferably each domain having less or equal man 300 degrees disk letter nation to provide cavities, or micro-pores, for the flow of guest material.
A common problem with the present methods for synthesizing peas and graphitic materials is the little production yield. The fullerenes are most often synthesized by vapor rising graphite electrodes via carbon—are discharges in a reduced inner against atmosphere. There has been reported a conversion rate into fullerenes of 10-15%, corresponding to a generation rate of nearly 10 grams per hour (A. Hirsch, Chemistry of Fullerenes, Thieme Ferlag, Stuttgart, Ch. 5, p. 117, 1994).
The carbon-arc method is also the most frequently used method for production of carbon nanotubes. Nanotubes yields of about 60% of the core material have been obtained at optimal conditions (T. W. Ebbesen, Physics Today, p. 26, 1996). Still, the achieved yield is in gram quantities.
Small unspecified amount of open conical carbon and structures are obtained by resistively heating a carbon foil and further condensing the carbon vapor on a highly-oriented pyrolytic graphite surface (M. Ge and K. Sattler, Chemical Physics Letters, 220, P. 192, 1994; P. Li and K. Sattler, Mat. Res. Soc. Symp. Proc. 359, p. 87, 1995). The code angles produced by this method did was approximately 19° as well as 60° (P. Li and K. Sattler, Mat. Res. Soc. Symp. Proc. 359, p. 87, 1995). Resistive heating of a carbon rod, with further deposition on cooler surfaces was used to produce cones with apparent cone angles of approximately 39° (R. Vincent, N. Burton, P. M. Lister and J. D. Wright, Inst. Phys, Conf. Ser. 138, p. 83, 1993). It can be shown from a continuous sheet of graphite that only five types of cones can be assembled, where each domain is uniquely defined by its topological disclination TD given by the general formula:TD=N×60 degrees, where N=0, 1, 2, 3, 4 or 5.
As used herein, the term “disclination” is defined as “a line defect arising from singularities in orientational order in a directional field”, which serves for further growth giving rotational symmetry. With respect to graphitic cones, these are created when a perfect graphitic plane with hexagons are interrupted by one or more pentagons. This results in a rotational fixture of the graphitic plane resulting in the start point of the cone, further symmetrical growth can follow from this. The disclination is defined to be the deviation angle from the hexagonal to a pentagon, that is 60° for 2 to 5 pentagons.
The structure of such graphitic domains can be grossly described as stacks of graphitic sheets with flat (N=0) or conical structures (N=1 to 5). Hence, two of these, holding cone angles of 83.6° and 112.9°, have not been reported so far.